The present invention relates to a device for watertight stoppering of bottles, through interchangeable glass stoppers, any bottle of one same series being able to be stopped by any stopper of the corresponding series.
At present, glass-to-glass interchangeable stoppering is obtained by roughening the outer surface of the stopper stem, and of the internal side of the bottle neck. The operations of grinding will produce a more or less rough surface, on the bottle neck as on the stopper stem. The glass-to-glass stoppering of the stopper stem on the bottle neck requires the addition of a lubricating grease on the bottle neck, in order to prevent both surfaces to seize each other, and to improve watertightness, such as is currently used in vacuum chambers.
For supplying a substitute for this application of lubricating grease, in order to obtain the above performances, it is possible to add into one or more grooves made into the stopper stem a flexible product which remains integral with this stopper. The resulting ring made of flexible matter has a tendency to rotate about the stopper stem in the groove (or grooves) of the stopper, according to the nature of the flexible product being used, when the stem and the bottle neck come in contact, the flexible product slipping into the bottom of said grooves.
For overcoming this disadvantage, during the moulding process of the bottle, the bottom of the groove, or grooves, of the stem is provided with notched teeth.
The depth variations resulting from the successive teeth and hollows determine difference of contraction of the flexible matter this contraction being dependent on the depth of the flexible matter itself. For this reason, when installed in a bottle neck, the external surface of the flexible ring consists of a successive series of facets, which are more or less rounded. The ring makes spaced-apart points of contact with the bottle neck instead of being perfectly circular concentrically to the stem. The engagement of these spaced facets on the bottle neck is a possible cause for lack of watertightness of the bottle, resulting in leakage of the liquid inside.